Bridge-operating machinery

ABSTRACT

Bridge-operating machinery, for rack-driven bascule spans, comprises heavy-duty gear-drive means connected to drive the racks and swing the span. A pair of counterpart, inverted, enclosed bridge-drive units (preferably incorporating speedreducer mechanisms) coupled to motor-driven shafting actuated through a differential drive delivers power to the racks; and each such bridge-drive unit includes parallel input, intermediate, and output shafts disposed with their axes in an irregular triangular array, with rigid, sealed structure mounting the shafts of each mechanism as a unitary assembly. Each of two, heavy, opposing walls of the housing structure is provided with three bearing-carrying openings, corresponding to the said array, which confront similar openings in the opposite wall; and shaft, and the gear means carried thereby, is journaled within one set of confronting openings in protected position within the housing structure, and with a drive pinion of each output shaft disposed exteriorly of its housing structure in engagement with a rack. The housing structure has mounting means adapting the unit for mounting in a variety of different positions, and location in such different positions, of each unitary drive assembly, with its irregular triangular array of gear-carrying shafts housed therein, adapts the mechanism for use in quite different bridge installations. Lubrication, protection, proper alignment, and ease of inspection and maintenance of the moving parts is assured.

Perkons et a1.

[ BRIDGE-OPERATING MACHINERY [75] Inventors: George Perkons; Orrell B.Schailey,

both of Philadelphia, Pa.

[73] Assignee: The Earle Gear and Machine Company, Philadelphia, Pa.

[22] Filed: Apr. 29, 1974 [21] Appl. No.: 465,099

[52] U.S. Cl. 14/38 [51] Int. Cl. E0ld 15/08 [58] Field of Search 14/38,40, 37, 39, 41

[56] References Cited UNlTED STATES PATENTS 708,348 9/1902 Hall 14/40719,153 [/1903 Smettcrs.... 14/40 1,659,250 2/1928 Erdal 14/41 FOREIGNPATENTS OR APPLICATIONS 595,733 10/1925 France 14/40 901,424 l/l954Germany l4/38 Primary Examiner-Nile C. Byers, Jr. Attorney, Agent, orFirm-Synnestvedt & Lechner [57] ABSTRACT Feb. 11, 1975 nected to drivethe racks and swing the span. A pair of counterpart, inverted, enclosedbridge-drive units (preferably incorporating speed-reducer mechanisms)coupled to motor-driven shafting actuated through a differential drivedelivers power to the racks; and each such bridge-drive unit includesparallel input. intermediate, and output shafts disposed with their axesin an irregular triangular array, with rigid. sealed structure mountingthe shafts of each mechanism as a unitary assembly. Each of two, heavy,opposing walls of the housing structure is provided with threebearingcarrying openings, corresponding to the said array, whichconfront similar openings in the opposite wall; and shaft, and the gearmeans carried thereby, is journaled within one set of confrontingopenings in protected position within the housing structure, and with adrive pinion of each output shaft disposed exteriorly of its housingstructure in engagement with a rack. The housing structure has mountingmeans adapting the unit for mounting in a variety of differentpositions, and location in such different positions, of each unitarydrive assembly, with its irregular triangular array of gear-carryingshafts housed therein, adapts the mechanism for use in quite differentbridge installations. Lubrication, protection, proper alignment, andease of inspection and maintenance of the moving parts is assured.

19 Claims, 9 Drawing Figures PATENTEUFEB' 3.864.777

SHEET 10F 6 PATENTEDFEB 3.864.777

SHEET 2 BF 6 AMA PATENTEB FEB] 1 I975 SHEET 3 0F 6 BRIDGE-OPERATINGMACHINERY BACKGROUND OF THE INVENTION This invention is concerned withbridge-operating machinery for movable span bridges, particularlybridges of either single or double-leaf bascule type, in which the span,or leaf, pivots about a horizontal axis in swinging to and from openposition.

Bridges of this kind, while widely used, have been subject toinstallation and maintenance problems. Many of these arise from thehostile environment in which the several sets of open gearing, whichcharacterize the prior art, are required to operate. These problems havebeen aggravated in recent years, as will be appreciated when it isrealized that a bridge which, years ago, might have been opened and shutperhaps only forty or fifty times in a year (or, at most, a few hundredtimes), today may be subjected to thousands of operations per year,because of the vast increase in boating activity, on the one hand, andthe high level of vehicular use of the bridge, on the other hand.

With more particular reference to installation problems, alignmentrequirements of the drive gearing have been severe, due to the manyindividual and separate shafts, bearings and gears which it wasnecessary to hold in close locational tolerance, to ensure properrelationships and tolerances throughout the drive train. In addition,since such equipment is used near bodies of water, frequently saltwater, it is subjected to the adverse effects of the elements, withsevere rust and corrosion and resultant high maintenance. Substantialmaintenance problems also have resulted from the presence, in theexposed machinery, of abrasive foreign material, such as sand, andvarious types of dirt and litter, including the accumulation ofdrippings from automobiles, droppings from pigeons and seagulls, and thelike. Furthermore, many detailed design differences have been requiredin adapting the bridge-operating machinery to different bridges.

In summary, the machinery previously available has not been fullysatisfactory because of installation, cleaning, and lubricationproblems, and because of the frequent necessity to repair and/or replaceand/or realign worn or damaged parts, and the lack of ready adaptabilityto differing environmental bridge structures.

SUMMARY OF THE INVENTION It is the general objective of this inventionto overcome the aforesaid problems by provision of improved basculebridge assemblies, and particularly improved gear-drive apparatus,adaptable to different installations, which apparatus is very simple toinstall and requires a minimum of maintenance. Specifically, theimproved apparatus assures proper lubrication, and exclusion of dirt,water, sand and other foreign material from the gears, and, accordingly,the apparatus is of improved reliability, while at the same time thesealed units of this invention are versatile as to differentinstallations.

In achievement of these general objectives, the invention providesnovel, unitary, sealed gear-drive units (usually including reductiongearing), in place of the open gearing previously employed; while at thesame time these units are configured to be readily adaptable for use inbridges of different designs, and may thus be substituted for theopen-gear trains of a variety of existing installations. Thisflexibility, of course, imposes the requirement that apparatus embodyingthe invention be capable of accommodating different positions of theinput, or primary, shaft, and/or of the output shaft which drives thebridge-carried rack. To meet this requirement in a simple and effectiveway, the invention utilizes input, intermediate, and output shaftsdisposed in an irregular triangular, parallel relation in novelcombination with a housing structure which includes spaced, parallelwalls, apertured to receive and mount the shafts, and versatile mountingmeans for the housing itself. The housing, with its shafts and gearing,constitutes a sealed unit which eliminates a number of intermediate,exposed bearings, bearing pedestals, and pillow blocks previouslyutilized in bridge installations. Also, and importantly, the novelapparatus makes it possible, whenever desired, to eliminate the outboardbearing previously required at the rack-driving pinion.

It is a feature that these units may be bodily shifted, verticallyand/or horizontally, and also rotated to, and installed in, differentpositions in which the input and- /or output shafts in one installationreside in different vertical and horizontal planes than those planeswhich they would occupy in another installation, so as to accommodatethe mechanism to different bridge structurcs, different foundations, anddifferent environmental conditions; and it is a further feature that inany of the various positions in which the unit may be mounted, theworking parts are assured of proper lubrication, and protection fromgrit, dirt and corrosion, and are yet readily inspected, and, ifnecessary, easily adjusted, repaired, or replaced.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a partly sectional and partly elevational view of a basculebridge, illustrating the main central drive unit and the invertedcounterpart right and lefthand improved bridge-drive units with theiroutput drive pinions engaging the arcuate racks carried by the maingirders of the bridge, which units in this embodiment includespeed-reduction gearing;

FIG. 2 is an enlarged fragmentary end view, taken as indicated by theline 22 of FIG. 1, and showing one main girder of the bridge and itsarcuate rack in full lines, in bridge-closed position, and in brokenlines in bridge-open position;

FIG. 3 is a partly sectional and partly elevational view of one of thesealed bridge-drive units, the view being taken as indicated by the line33 of FIG. 4;

FIG. 4 is a sectional plan view of the bridge-drive unit, the view beingtaken as shown by line 4-4 of FIG.

FIG. 5 is a cross-sectional view taken on the line 5--5 of FIG. 3;

FIG. 6 is a cross-sectional view taken on the line 66 of FIG. 3;

FIG. 7 is a fragmentary, somewhat schematic, view of a differentinstallation, in which the bridge-drive unit occupies a position whichis rotated with respect to the position of the unit as illustrated inthe embodiment of FIGS. 1 to 6;

FIG. 8 is a similar view, showing said unit mounted in an obliqueposition, as compared with the other two illustrated positions; and

FIG. 9 is a somewhat diagrammatic showing of the bridge-drive unit,partially modified, by the use of an adapter casing-element, so as toaccommodate a differ- DETAILED DESCRIPTION OF THE INVENTION Although,generally, what is the righthand side of a bridge and what the lefthandside depends upon which way one is facing the bridge, in what followsthe structure at the right of FIG. 1 will be considered as being at therighthand side of the bridge, while the structure at the left of thatFigure will be considered as being at the lefthand side of the bridge.

With initial reference to FIG. I, there is illustrated the movable span,or Ieafl0, of a bascule bridge. The leaf, shown in section, is of knowntype and may comprise a roadbed 11 with longitudinal channel members 12,and with stringersor l-beams l3, and other structure includingtransverse members (not shown), all supported by right and left main,bascule girders l4 and 14a, and supplementary girders 16, 16a. Right andlefthand trunnions 15, 15a are disposed in axial alignment and providepivotal support for the leaf by virtue of pivotal mounting of the pairof main griders 14, 14a, and the pair of supplementary trunnion girders16, 16a, upon the trunnions 15, a, as is known. to accommodate swingingmovements of the span about the axis, a, defined by the trunnions, eachtrunnion is pivotally mounted within a trunnion bearing, enclosed withinthe housing 17, 17' (or 17a, 17a), the bearing housings beingrespectively carried by the bearing plates 18, 18a, on pedestals 19,19a.

The leaf 10 is swingable with respect to the fixed bridge structure,right and lefthand portions of which are shown at 20 and 20a. Toaccomplish this swinging movement, as is well illustrated in FIG. 2,each of the main bascule girders has rigidly secured thereto a rack (22for the righthand girder l4 and 22a for the lefthand girder 14a) whichrack is arcuately curved about the trunnion-defined axis a. As will beclear from FIGS. 1 and 2, the main girders l4 and 14a of the bridge,which substantially define its swingable span, pivot about the trunnionaxis in response to delivery of power to the racks 22, 22a, in themanner to be described.

FIG. 2 shows righthand main girder 14 in full lines in bridge-closedposition, and in broken lines in open position. The main girders carry acounterweight C, such as is shown in FIG. 2, although omitted from FIG.1, in the interest of clarity of illustration.

In accordance with known practice, motor-driven gear means is providedto drive the arcuately curved racks 22 and 22a. This latter meanscomprises a motor 23 which may, as shown, drive a central speed reducer24 (preferably a differential type), which is coupled to shafting 25.The shafting 25 comprises right and lefthand shaft sections 26 and 27,respectively; and a pair of couplings 28, 28, serve to connect theseshaft sections to the central speed reducer differential-gear unit 24.The right and lefthand shaft sections, which comprise the shafting 25,extend in the direction of span width and in general parallelism withthe trunnion axis In especial accordance with the present invention, apair of bridge'drive units 29, 29a are interposed between shafts 26 and27 and the respective racks 22 and 22a. These unitary devices areidentical, inverted, i.e., mirror-image, counterparts, so that they havereversed left and right presentation of their input and output shafts.Therefore, only the one at the right of FIG. 1 will be described indetail. Each of these units is a housed gearing unit. They may include(though not necessarily) one or more stages of gear reduction; and inthe present embodiment, each incorporates two stages of reduction, sothat a relatively small input shaft may be employed. More stages ofreduction may be incorporated, if needed. The respective bridge-driveunits rest upon bed plates 30, 30a, which plates, in turn, are carriedby pedestals 31, 31a. Substantial anchor bolts A are preferably used tosecure each unit, as shown in FIG. 2. The units have input shafts 32,32a which are coupled, each through one of a pair of coupling units 33,33a, to the respective shaft sections 26, 27, of drive shafting 25. Forexample, the input shaft 32 of the right-hand speed-reducer unit 29 iscoupled, through coupling 33, to shaft 26. Each unit has an output shaft34, or 34a, which carries a pinion 35, or 35a, in driving engagementwith an associated one of the racks 22, 22a.

Whereas, prior to this invention, the coupling of the cross-shafting tothe racks was accomplished through the intermediation of a number ofshafts, gears, intermediate bearings, bearing pedestals, and the like,all of which were exposed to the elements, in the present invention useis made of the versatile, housed units, 29, 29a. Each unit is especiallyconfigured and mounted to protect it from moisture, corrosion, dirt, andthe like. As will become clear, as the description proceeds, these unitsnot only may be substituted for the open gearing of existinginstallations, but each may be shifted vertically and/or horizontally todifferent locations and also may be mounted in a variety of differentangular positions, about any one of the shaft axes, or about an axisparallel thereto, and can be used to drive bridge-carried racks ofbridges of specifically different design, and to make adaptation fordifferently located central power mechanism, and also for differences infoundations or environmental arrangements. To this end the unitspreferably have input, intermediate, and output shafts, disposed intriangular parallelism, with differing sides in the triangle, and suchshafts are mounted in special relationship to novel housing structure,which journals the units, reduces the number of parts, and seals andprotects all of such parts.

The righthand, unitary speed-reducing bridge-drive mechanism (unit 29)will now be described, with particular reference to FIGS. 3 to 6,inclusive. This unitary mechanism includes three parallel shaftsdisposed in a particular triangular array, hereinafter more fullydiscussed. The first two of these shafts comprise the above-mentionedinput shaft 32 carrying an input pinion 32p, and an intermediate shaft36 carrying a gear 36g, which latter is in driven engagement with saidinput pinion 32p. The third shaft comprises the output shaft 34 whichhas a driven gear 34g in engagement with a pinion 36p carried by saidintermediate shaft 36 (see particularly FIGS. 3 and 4). The output shaft34 also carries, and thus drives, the above-mentioned output pinion 35which is, in turn, in driving engagement with the teeth 22b of rack 22(FIGS. I and 2).

This parallel and triangular arrangement of the input, intermediate, andoutput shafts lends itself particularly well to simplified mounting, andincorporation into a single separately handleable unit. As will becomeclear from what follows, the three shafts may be arranged in arraysomewhat different from the triangulation to be found in the embodimentillustrated in FIGS. 1 through 6. However, the invention contemplatessuch changes in array, without departing from the concept of providingbridge-drive mechanisms which comprise sealed, unitary, preferablyspeed-reducing gear devices, adaptable to different positions and todifferent environmental structures.

As will now be understood, various of the advantages of this inventionare achieved by disposing the triangulated input, intermediate, andoutput shafts in a rigid housing structure including two verysubstantial parallel spaced walls, each having three bearing-carryingopenings disposed in triangular array corresponding to the shaft array.A set of three openings in one of these two walls is aligned with andconfronts a corresponding set in the opposite wall. These openings, andthe bearings carried thereby, serve to journal the shafts with theirgears sealed within the housing structure. For example, bearing meansprovided in one of the spaced walls serves to journal a portion 34d ofthe output shaft 34, which, at its outboard end 340, carries therackdriving pinion 35.

Now making still more detailed reference to the construction of the unit29, and to the manner in which the shaftsand gears are housed andprotected, inspection of FIGS. 4 and 6 shows that the housing structurecomprises a pair of spaced side walls 37 and 38, of heavy construction,each of which carries bearings. To that end, each wall is provided withthree primary bearingcarrying apertures which receive the input,intermediate and output shafts 32, 36 and 34, respectively. The housingalso has heavy wall structure 39, perpendicular to walls 37 and 38,which may serve as a mounting base, either with the unit 29 in theposition shown in FIGS. 1 to 6, or in various other positions, such, forexample, as the positions shown in FIG. 7 when mounted against avertical supporting structure 3l-V, or the oblique position shown inFIG. 8. The housing of unit 29 also has a pair of walls 40 and 4!, and awelded cover 42, with a removable access panel P for ready inspectionand lubrication regardless of the mounted position of the unit.

Thus, with one triangular arrangement of the axes of the three shafts32, 36 and 34, a considerable variety of locations of the central powerstructure 23, 24, and the drive shaft 26, and also of the rack 22, maybe accommodated by a single from of drive-unit 29. In addition, itshould be noted that two of the shafts in the unit, preferably the twoshafts carrying the heaviest loads, i.e., shafts 34 and 36, may belocated with their axes on the common plane of separation S of thehousing; while the shaft 32 (of least load), which carries the smallestpinion (32p) is the only shaft located in what is here termed the lowerbox of the housing and this shaft, with its pinion 32p may be readilyslipped in and out of the housing, through the aperture 43 hereinafterreferred to, without the necessity of opening up the whole housing. Ifeither of the shafts 34 and 36, and/or their gearing and/or bearings,require inspection, repair, or replacement (beyond what may beaccomplished by opening of the cover plate P), it is a rela tivelysimple matter to do so by separating the upper and lower box-likestructures, along the plane of separation S. Other features of advantageof this arrangement will be brought out hereinafter.

It should here be noted that the heavy bearingsupporting walls 37 and38, and the lighter walls (at right angles thereto) 40 and 41, haveupper and lower portions (when considering the unit 29 as being mountedin the position shown in FIGS. 1 to 6). the lower portions 37, 38, 40and 41 with the fifth wall. 39, which joins all of them, constituting abox-like structure; and the upper portions 37". 38". 40", 41", with thewelded cover assembly 42 (having removable access plate P) unitedthereto, constituting another box structure, inverted with relation tothe one first mentioned, and these box structures have mating surfacesalong a common plane of separation S. Securing flanges F and F" areprovided at the ends shown in FIGS. 3 and 4; and a thick stiffeningstructure may be provided at 37T' and 37T", adjacent to the rackdrivingpinion 35, as shown in FIGS. 3 and 4. The housing formed by all of theabove elements may be secured together by various screws, bolts, orother suitable fasteners B1, B2 and B3, as seen in FIGS. 3 and 4.

Considering further the specific arrangement shown in FIGS. 1 to 6, theparallel triangulation of the three shafts clearly appears in FIG. 3,and the apertures in confronting walls 37 and 38 are disposed incorresponding array. Referring to the input shaft 32, for example, itwill be seen that the wall member 38' is apertured at 43 (FIG. 6), andthat the wall member 37' is apertured at 44, to receive and journal theshaft 32. Conical roller bearings 43a and 43b, which combine radialbearing and thrust functions, are seated within the recessed openings 43and 44, respectively. A packing gland, designated generally at 45, sealsthe input end of the shaft, whereas a gasketed cover 46 shields theopposite end of the shaft.

Directly above the input shaft 32 lies the intermediate shaft 36 (FIGS.3 and 6), which carries the intermediate'gear 36g disposed in drivenengagement with the input pinion 32p. As described above, shaft 36 alsocarries the intermediate pinion 36p disposed in driving engagement withthe output gear 34g. The intermediate shaft 36 terminates in an endportion 360 which is mounted within an aperture 47 provided in wall 37(FIG. 6).

Bearing B may be positioned and adjusted by the cap structure 36d whichalso seals the aperture 47. The bearing B and cap 36d support the end360 of the intermediate shaft 36, in manner similar to the describedsupport and sealing of a similar portion of input shaft 32. Wall 38 isapertured at 47a in alignment with the aperture 47 provided in wall 37,and this aperture 470 receives the bearing 48 and the cap 49 whichrespectively journal and enclose that end of the intermediate shaftwhich terminates at the said housing wall 38.

Referring particularly to FIGS. 4 and 5, it will be seen that the outputshaft 34 has one of its ends 340 mounted by bearings in an aperture 34in wall 38; that end being carried by double, conical roller bearings50, mounted in a bearing cartridge 50a. Also, that end of the shaftassembly is sealed by the gasketed member 51. The output shaft gear 343is carried by an intermediate portion of the shaft 34, between theapertured walls 37 and 38, and said output shaft gear is, as mentionedabove, driven by the intermediate pinion 36p. Portion 34d of outputshaft 34 extends through aperture 34" of the wall 37 of the housing,(which latter aperture confronts the aperture 34') and is supported insaid wall by double-conical bearings 52, which serve r 7 also to takeloads imposed by the pinion 35, which drives the bridge-carried rack 22(FIG. 2). A sealcarrying cap G provides a seal around shaft portion 34d.

The pinions and gears are either formed integrally with the shafts, orare secured to their respective shafts by the use of keys. For example,the gear 34g will be seen to be keyed, at 53, to the output shaft (FIG.4). Such securement, or integral formation, of the individual gears willbe apparent from the drawings and understood without detaileddescription.

To facilitate assembly of the mechanism, the rigid housing structure issplit into two dished sections (upper and lower sections as seen inFIGS. 1 to 6); as heretofore described. When the mechanism is assembled,the intermediate shaft 36, with its components assembled thereon, islowered without difficulty into the semicylindrical cavities which formthe lower halves of the housing apertures 47 and 47a. Similarly, theoutput shaft, with its components assembled thereon, is lowered into thesemicylindrical cavities which form the lower halves of the housingapertures 34 and 34". The aperture 43 in the wall 38 of the housing islarge enough to permit insertion of shaft 32 and pinion 32p through thataperture.

The housng described above is, of course, supplied with suitablelubricant, and it will be appreciated that, unlike prior artarrangements, only the final output pinion 35 is disposed exteriorly ofthe housing, its shaft 34 being supported inboard, by the bearings 52and 50. In this way the maintenance requirements of the apparatus aregreatly reduced.

In the interest of simplicity of illustration, the gears have been shownas spur gears. However, it will be understood that it may be desirableto use other types of gearing. For example, herringbone, helical,orother forms of gears may be employed.

With regard to installation of the described mechanism, in position todrive the bridge-carried racks (see FIGS. 1 and 2), it will now beappreciated that all of the shafts, gears, bearings, and the like, atone side of the bridge, are carried as a single unit, and that thisvirtually disposes of problems of initial tolerance and alignment, andproblems relating to maintenance thereof within the drive train, such asare otherwise encountered in the field.

The flexibility of bridge design which these speedreducer'units affordwill be clear when it is recognized that the units may be rotated tovarious different positions to accommodate input and output shaftsresiding in vertical and horizontal planes, which differ from thoseplanes which appear in the apparatus illustrated in FIGS. 1 to 6. Forexample, as shown in FIG. 7, a re ducer unit 29 having shafttriangulation exactly like that already described, can be mounted in aposition which is rotated 90 with respect to the position of the unit asillustrated in FIGS. 1 to 6. When utilized in a bridge having thisdesign requirement, the output shaft 34 is disposed vertically above theintermediate shaft 36, rather than to one side thereof, and the pinion35 is engaged with a bridge-driving rack at a location indicatedfragmentarily at 22'.

As shown in FIG. 8, an oblique mounting may readily be employed to meetstill other installation requirements.

Within the purview of this invention, and in addition to theadaptability provided by freedom to variously mount the drive unit (asshown by FIGS. 2, 7 and 8), the triangulation of the shafts may also bevaried, further to adapt the concepts of the invention to differentbridge installations. The array shown in FIGS. 1 to 8 is on shaftcenters forming an irregular right-angled triangle. An alternativetriangular array is shown, somewhat diagrammatically, by the unit 29 inFIG. 9. Here. the shafts 36 and 34 are on the separation plane S of thecasing (as before) but the input shaft 32 lies somewhat closer to theoutput shaft 34 than in the structure of FIGS. 1 to 8, forming, in thisinstance, a scalene triangular arrangement.

The same shafts, pinions and gears may here be used, as in the mechanismof FIGS. 1 to 8, but the center of shaft 32 is here located higher thanit is in FIG. 7 (when the unit is mounted in a vertical position). Ascompared with FIG. 2, if the unit of FIG. 9 were mounted horizontally,the input shaft 32 would be disposed womewhat more to the right than itappears in FIG. 2. Parallelism of the shafts is retained. Utilization ofthis shaft array, or of others which can be devised, in novelcombination with the split housing structure 29' in accordance with FIG.9, requires only that the housing structure be modified to providebearing-carrying openings in correspondence with the selected shaftarray. If this is done, all of the above-described benefits areachieved.

In the arrangement shown in FIG. 9 (as in the arrangement of FIG. 7) theportion of the casing disposed toward the right may be considered simplyas an adapter element. A differently-located mounting for shaft 32 isall that is required, as between these two interchangeable casingelements. For convenience, such casing element in FIG. 7 is designatedE1, while that in FIG. 9 is designated E2. If desired, alternativemounting of the casing in different positions, upon foundations or otherstructures variously located, may be facilitated by providing casingelement E2 with several heavy mounting walls, such as seen at 39a, 39band 39c. FIG. 9 also shows an alternative location of the rack, as seenat 22".

It will readily be seen that the sealed drive unit will provide andmaintain adequate lubrication of all moving parts within the casing, inany of the mounting positions for which the unit is adapted, since theconfiguration is such that one or more of the pinions and gears willsubject it to the oil bath in the casing and will act to carry or splashoil on other moving parts.

It should also be noted that in the event of failure of any part of themechanism, or in case of wear of parts beyond a predetermined limit, theentire bridge-drive unit may be disconnected from its foundation, andthe coupling of the input shaft also disconnects, and the entire unitcan then be pulled or lifted out of the bridge installation, and acounterpart unit put into place and coupled up for operation, with aminimum down-time for the bridge as a whole.

In conclusion, it is intended that the entire disclosure be consideredas illustrative, and as limited only by the claims, and that the latterbe construed as broadly as permitted by the prior art.

We claim:

1. A bascule bridge assembly comprising a rack at each side of thebridge, counterpart inverted right and left-hand sealed gear-driveunits, each having an outwardly-extending shaft carrying an externalpinion engaging one of said racks, each of said units having apower-input shaft having an external connection device, and apower-actuated differential-drive mechanism disposed between saidinverted units and coupled to said external connection devices.

2. ln bridge-operating machinery having power-drive shafting and abridge-operating rack, a sealed geardrive unit operatively associatedwith said shafting and said rack, and comprising a plurality of gearedshafts, including a powerinput shaft, a rack-driving output shaft and anintermediate shaft, and further comprising a split housing having atleast two cooperating casing members configured with mating surfacesadapted to be sealed together and having, adjacent to said surfaces,mounting means for bearings of a plurality of spaced-apart gearedshafts, one of which is said output shaft which extends outside of thehousing and there carries a pinion positioned to actuate the rack, andanother of which is the said intermediate shaft, and one of said casingmembers carries bearing means for the power-input shaft which has meansfor coupling it to said power-drive shafting, said input shaft beingcentered on an axis spaced from the centers of the two shaftsfirst-mentioned, in such relation that the three mentioned shaft centersare at points forming a triangle.

3. The construction of claim 2 wherein the said coupling means and saidrack-driving pinion are at opposite sides of said housing.

4. The construction of claim 2 wherein the housing has means formounting it in any one of a plurality of positions so as to accommodatedifferent relative locations of said shafting and said rack with respectto an environmental base.

5. The construction of claim 2 wherein said triangle is an irregulartriangle.

6. The construction of claim 2 wherein said triangle is a right-angledtriangle.

7. The construction of claim 2 wherein said casing member which carriesbearing means for said input shaft is formed as a replaceable adapterelement whereby the location of the axial cneter of the input shaft maybe altered relative to the location of another shaft center.

8. The construction of claim 4 wherein the housing comprises heavyopposed walls adapted to carry the mounting means for the shaftbearings, and the means for mounting the housing includes rigidstructure generally at right angles to said walls.

9. The construction of claim 8 wherein the lastnamed structure isgenerally parallel with the shaft axes.

10. The construction of claim 2 wherein at least two of the gearedshafts comprise reduction gearing.

11. The construction of claim 2 wherein there is reduction gearingbetween the input shaft and said intermediate shaft and also between thelatter and the said output shaft.

12. The construction of claim 4 wherein the sealed housing provides alubricant vessel so configured as to lubricate housed gearing thereinregardless of the position in which the unit is mounted.

13. The construction of claim 4 wherein a removable access cover is sopositioned on the housing as to be accessible in the various positionsof mounting of the unit.

14. In a bascule bridge construction, trunnion means, a bascule spanpivotally supported upon said trunnion means, to accommodate swingingmovements of said span, about an axis defined by said trunnion means, anarcuately curved rack secured to said bascule span with its center ofcurvature on said axis. and heavy-duty gear-drive means for driving saidrack to swing said span and movable for opening and closing of thelatter, said gear-drive means comprising: motor-driven shafting; aspeed-reducer mechanism for delivering power from said shafting to saidrack, said mechanism including at least three parallel shafts, disposedin triangular array and comprising a gear-carrying input shaft coupledto said shafting, a gear-carrying intermediate shaft in drivenengagement gear-carrying said input shaft, and a gear-carring outputshaft in driven engagement with said intermediate shaft, said outputshaft carrying a pinion disposed to drive said rack; and means mountingsaid speed-reducer mechanism as a unitary sealed assembly, said lastmeans comprising rigid housing structure including parallel, spaced,walls each having openings disposed in triangular array corresponding tothe shaft array, and confronting similar openings in the other wall, oneset of corresponding and confronting openings serving to mount saidinput shaft within said housing structure, another set of correspondingand confronting openings serving to mount said intermediate shaft withinsaid housing structure, and a third set of corresponding and confrontingopenings serving to mount said output shaft within said housingstructure, a portion of said output shaft extending through one of theconfronting openings of the third set and carrying said pinion.

15. A bridge construction in accordance with claim 14 and in which saidrigid housing structure includes two complementary, dished sectionsconfigured and disposed to define said parallel spaced walls and tomount and seal said speed-reducer mechanism, each section terminating inmating surfaces confronting and sealed against similar surfaces of theother section, said surfaces lying generally in a plane containing theaxes of two of said three parallel shafts, and said two sections of saidhousing structures being separably secured at said plane.

16. A bridge construction as defined in claim 15 and furthercharacterized in that said two shafts comprise said intermediate shaftand said output shaft.

17. A bridge construction as defined in claim 16 and furthercharacterized in that: the portion of said input shaft which is coupledto said shafting extends through a wall region of one only of saidsections.

18. In a bascule bridge construction, a pair of trunnions, a basculespan including spaced main girder means each pivotally supported upon acorresponding one of said pair of trunnions, to accommodate swingingmovements of said span about an axis defined by said trunnions, a pairof arcuately curved racks, each secured to a corresponding one of saidmain girder means with its center of curvature on said axis, andheavy-duty gear-drive means for driving said racks to swing said spanand provide for opening and closing of the latter, said gear-drive meanscomprising: motor means; shafting coupled to said motor means, extendingin general parallelism with said axis, and substantially spanning thedistance between the girder-supported racks; a pair of speed-reducermechanisms for delivering power from portions of said shafting to acorresponding one of said racks, each speed-reducer mechanism includingthree parallel shafts, disposed in triangular array, and comprising aninput shaft coupled to said shafting and carrying an input pinion, anintermediate shaft carrying an intermediate gear in driven engagementwith said input pinion and carrying a second pinion, and an output shaftcarrying an output pinion and having a gear in driven engagement withsaid intermediate pinion, the output pinion of each speed-reducermechanism being in driving engagement with one of said racks; and meansmounting each such speed-reducer mechanism as a single unitary assemblyand protecting the same from corrosion, dirt and the like, said lastmeans comprising rigid housing structure including parallel, spaced,walls each having three bearing-carrying openings disposed in triangulararray corresponding to the shaft array, and confronting similar openingsin the other wall, one set of corresponding and confronting openings,and the bearings thereof, serving to journal said input shaft with itspinion enclosed within said housing structure, another set ofcorresponding and confronting openings, and the bearings thereof,serving to journal said intermediate shaft with its gear and its pinionenclosed within said housing structure. and a third set of correspondingand confronting openings, and the bearings thereof, serving to journalsaid output shaft with its driven gear enclosed within said housingstructure and its rack-driving pinion mounted exteriorly of said housingstructure upon a free end portion of said output shaft which extendsthrough one of the confronting openings of said third set.

19. A bridge construction in accordance with claim 18 and furtherincluding means sealing said shafts in the bearing-carrying openings insaid spaced walls.

1. A bascule bridge assembly comprising a rack at each side of thebridge, counterpart inverted right and left-hand sealed gear-driveunits, each having an outwardly-extending shaft carrying an externalpinion engaging one of said racks, each of said units having apower-input shaft having an external connection device, and apower-actuated differential-drive mechanism disposed between saidinverted units and coupled to said external connection devices.
 2. Inbridge-operating machinery having power-drive shafting and abridge-operating rack, a sealed gear-drive unit operatively associatedwith said shafting and said rack, and comprising a plurality of gearedshafts, including a powerinput shaft, a rack-driving output shaft and anintermediate shaft, and further comprising a split housing having atleast two cooperating casing members configured with mating surfacesadapted to be sealed together and having, adjacent to said surfaces,mounting means for bearings of a plurality of spaced-apart gearedshafts, one of which is said output shaft which extends outside of thehousing and there carries a pinion positioned to actuate the rack, andanother of which is the said intermediate shaft, and one of said casingmembers carries bearing means for the power-input shaft which has meansfor coupling it to said power-drive shafting, said input shaft beingcentered on an axis spaced from the centers of the two shaftsfirst-mentioned, in such relation that the three mentioned shaft centersare at points forming a triangle.
 3. The construction of claim 2 whereinthe said coupling means and said rack-driving pinion are at oppositesides of said housing.
 4. The construction of claim 2 wherein thehousing has means for mounting it in any one of a plurality of positionsso as to accommodate different relative locations of said shafting andsaid rack with respect to an environmental base.
 5. The construction ofclaim 2 wherein said triangle is an irregular triangle.
 6. Theconstruction of claim 2 wherein said triangle is a right-angledtriangle.
 7. The construction of claim 2 wherein said casing memberwhich carries bearing means for said input shaft is formed as areplaceable adapter element whereby the location of the axial cneter ofthe input shaft may be altered relative to the location of another shaftcenter.
 8. The construction of claim 4 wherein the housing comprisesheavy opposed walls adapted to carry the mounting means for the shaftbearings, and the means for mounting the housing includes rigidstructure generally at right angles to said walls.
 9. The constructionof claim 8 wherein the last-named structure is generally parallel withthe shaft axes.
 10. The construction of claim 2 wherein at least two ofthe geared shafts comprise reduction gearing.
 11. The construction ofclaim 2 wherein there is reduction gearing between the input shaft andsaid intermediate shaft and also between the latter and the said outputshaft.
 12. The construction of claim 4 wherein the sealed housingprovides a lubricant vessel so configured as to lubricate housed gearingtherein regardless of the position in which the unit is mounted.
 13. Theconstruction of claim 4 wherein a removable access cover is sopositioned on the housing as to be accessible in the various positionsof mounting of the unit.
 14. In a bascule bridge construction, trunnionmeans, a bascule span pivotally supported upon said trunnion means, toaccommodate swinging movements of said span, about an axis defined bysaid trunnion means, an arcuately curved rack secured to said basculespan with its center of curvature on said axis, and heavy-dutygear-drive means for driving said rack to swing said span and movablefor opening and closing of the latter, said gear-drive means comprising:motor-driven shafting; a speed-reducer mechanism for delivering powerfrom said shafting to said rack, said mechanism including at least threeparallel shafts, disposed in triangular array and comprising agear-carrying input shaft coupled to said shafting, a gear-carryingintermediate shaft in driven engagement gear-carrying said input shaft,and a gear-carring output shaft in driven engagement with saidintermediate shaft, said output shaft carrying a pinion disposed todrive said rack; and means mounting said speed-reducer mechanism as aunitary sealed assembly, said last means comprising rigid housingstructure including parallel, spaced, walls each having openingsdisposed in triangular array corresponding to the shaft array, andconfronting similar openings in the other wall, one set of correspondingand confronting openings serving to mount said input shaft within saidhousing structure, another set of corresponding and confronting openingsserving to mount said intermediate shaft within said housing structure,and a third set of corresponding and confronting openings serving tomount said output shaft within said housing structure, a portion of saidoutput shaft extending through one of the confronting openings of thethird set and carrying said pinion.
 15. A bridge construction inaccordance with claim 14 and in which said rigid housing structureincludes two complementary, dished sections configured and disposed todefine said parallel spaced walls and to mount and seal saidspeed-reducer mechanism, each section terminating in mating surfacesconfronting and sealed against similar surfaces of the other section,said surfaces lying generally in a plane containing the axes of two ofsaid three parallel shafts, and said two sections of said housingstructures being separably secured at said plane.
 16. A bridgeconstruction as defined in claim 15 and further characterized in thatsaid two shafts comprise said intermediate shaft and said output shaft.17. A bridge construction as defined in claim 16 and furthercharacterized in that: the portion of said input shaft which is coupledto said shafting extends through a wall region of one only of saidsections.
 18. In a bascule bridge construction, a pair of trunnions, abascule span including spaced main girder means each pivotally suppOrtedupon a corresponding one of said pair of trunnions, to accommodateswinging movements of said span about an axis defined by said trunnions,a pair of arcuately curved racks, each secured to a corresponding one ofsaid main girder means with its center of curvature on said axis, andheavy-duty gear-drive means for driving said racks to swing said spanand provide for opening and closing of the latter, said gear-drive meanscomprising: motor means; shafting coupled to said motor means, extendingin general parallelism with said axis, and substantially spanning thedistance between the girder-supported racks; a pair of speedreducermechanisms for delivering power from portions of said shafting to acorresponding one of said racks, each speed-reducer mechanism includingthree parallel shafts, disposed in triangular array, and comprising aninput shaft coupled to said shafting and carrying an input pinion, anintermediate shaft carrying an intermediate gear in driven engagementwith said input pinion and carrying a second pinion, and an output shaftcarrying an output pinion and having a gear in driven engagement withsaid intermediate pinion, the output pinion of each speed-reducermechanism being in driving engagement with one of said racks; and meansmounting each such speed-reducer mechanism as a single unitary assemblyand protecting the same from corrosion, dirt and the like, said lastmeans comprising rigid housing structure including parallel, spaced,walls each having three bearingcarrying openings disposed in triangulararray corresponding to the shaft array, and confronting similar openingsin the other wall, one set of corresponding and confronting openings,and the bearings thereof, serving to journal said input shaft with itspinion enclosed within said housing structure, another set ofcorresponding and confronting openings, and the bearings thereof,serving to journal said intermediate shaft with its gear and its pinionenclosed within said housing structure, and a third set of correspondingand confronting openings, and the bearings thereof, serving to journalsaid output shaft with its driven gear enclosed within said housingstructure and its rack-driving pinion mounted exteriorly of said housingstructure upon a free end portion of said output shaft which extendsthrough one of the confronting openings of said third set.
 19. A bridgeconstruction in accordance with claim 18 and further including meanssealing said shafts in the bearing-carrying openings in said spacedwalls.